Hot data identification is a process or technique is which data is classified or identified as being either hot or cold. Hot data (generally speaking) is data that will be invalidated shortly in the future. Cold data (generally speaking) is data that will remain valid for a long time in the future. In one example application, solid state storage systems use hot data identification techniques to group hot data together and cold data together, for example when host writes are received (e.g., hot data is written to the cache whereas cold data is written to the larger but slower main drive) or during garbage collection (e.g., hot data in a block being garbage collected is written to a first new block whereas cold data in that same block is written to a second new block). Although a number of hot data identification techniques exist, improved hot data identification techniques would be desirable. Such improved techniques may (for example) improve the accuracy of hot data identification, which in turn improves the efficiency of the solid state system (e.g., by reducing write amplification, which is defined as the ratio of the number of writes to solid state storage compared to the number of host writes).